Project Summary Spatial memory is an essential resource that is used by individuals every day, be it navigating to work, to school, or back home. The study of how individuals learn new spatial environments is particularly important with regards to aging, because spatial memory deteriorates with age and disease (e.g., Alzheimer's disease), and deterioration can have a significant impact on individuals' lives. Despite decades of research, one issue that has been particularly difficult to study is the development of spatial memories and cognitive maps in large scale, real-world environments. Specifically, how do individuals translate their exposure to a new environment into an understanding of that environment? This issue is extremely important for understanding why spatial learning may become difficult as individuals age or how spatial confusion could be minimized. The PI has developed research software that utilizes Google Street View, to rapidly and easily virtualize real-world environments. Using this software, the researchers will investigate how spatial representations that support navigation in familiar environments develop over time, both cognitively and neurally. Inspired by animal research showing that hippocampal place-cells, which track an animal's position in space while it navigates, replay during periods of quiet wakefulness after a novel environment is experienced, we hypothesize that, in humans, the kind of cognitive maps that develop can be influenced by having participants selectively reminisce about certain aspects of recent navigation experiences. The first experiment will use a novel training paradigm, wherein participants will learn an environment by navigating through it, and memory retrieval tasks will be used to affect the kinds of cognitive maps that individuals then form. Cognitive maps will then be assessed by examining how participants navigate novel routes in the learned environment. This experiment will be followed by an fMRI study, which will examine the neural representations of space that develop over the training period, investigating how dynamic activity in areas such as the hippocampus support specific aspects of navigation and how this activity changes based on experience and on the kind of memory retrieval tasks that are influencing the development of the cognitive maps. This work will be the first to provide a framework for the development of cognitive maps in large scale, real-world environments, as well as the first investigation of the hypothesis that post-encoding memory retrieval can influence the kinds of cognitive maps that develop. These findings will have broad appeal to the research community but also, potentially, practical and clinical relevance, especially for older adults or individuals with selective hippocampal impairments.